Euler Totient Function

phi.py

def phi(n):
    if n == 1:
        return 1
    phi = 1
    d = 2 
    while n > 1:
        count = 0 
        while n % d == 0:
            count += 1
            n /= d
        if count > 0:
            phi *= (d**(count-1))*(d-1)
        d = d + 1
        if d*d > n:
            if n > 1: 
                phi *= int(n - 1)
            break
    return phi